Improvement in hot-air furnaces



T. F. HEMMICH. HOT-AIP. FURNACE.

4the same at the line a: a'.

UNITED 4STATES,

PATENT OFFICE.

THOMAS F. HEMMICH, OF READING, PENNSYLVANIA, ASSIGNOR TO AHIM- SELF AND ELIAS FRITZ, SR., OF SAME PLACE.

' IMPROVEMENT IN Hor-AIR FuRNAcEs.

Specification forming part of Letters Patent N o. 171,281, dated December 21, 1875; application filed A October 25, 1875.

ment in Heating-Furnaces, of which the following is a specification:

The object of this invention Ais to introduce the air to be heated through a trunk or ,case that is central within the lire, whereby the re forms a ring around such air-tube, and exerts a great influence upon the same, to heat the atmospheric air passing through the same.

In the drawing, Figure l is a vertical section of the said furnace. Fig. 2 is a plan of The base b4 is made as an annular channel, d, above which are the .gratese e, formed as sections, set in a I ring-frame, i, and this ringframe i and grates can be revolved by the crank and pinion la acting upon the teeth 2 upon the said ring-frame. The frame i rests upon rollers 8, and each grate may be hinged so as to be dropped by moving a button. There is also a case, b1, and door at b2, that give access to the space below the grates, andl regulate the supply of air to the re. This means of moving the grate is employed in stirring the fire, and freeing the same from ashes.

The ashes that fall into the annular trough or channel d are scraped around by Scrapers i', upon the circular frame z', and fall away, through the openin g or trunk k, into any suitable ash-pit, at 7a.

The outer casing or fire-pot Z is extended up, preferably, with two other casings or cylinders, Z1 l2, and in the casing Z1 there are the supply-chutes m, with doors, or'with coal feeders or magazines, as indicatediby dotted lines. The center air-tube or cylinder c is continued upwardly with an inverted. conical casing, n, so that the space over the ring of fire is contracted, and thereby the products of combustion are made to impinge upon the metal casings, and heat them and the atmosphere that is in contact with their exterior surfaces.

Aring, o, closes the space between the outer and inner casings at the top; but there are verpel the heat to be given out through the cas-` ings, but at the same time the draft is direct. The pipe s may, however, open into a descending due.

At the upper end of the furnace there is a clamping-bar, t, with arms resting upon the ring-plate o, and a single tie-bolt, a, passing through the same, and to the base of the furnace, serves to hold the entire furnace together.v

When this furnace is set upon a foundation of masonry, as illustrated by dotted lines at wf, the cylindrical base-plate w rests directly upon such masonry, and there is a central opening in such plate, and the masonry is hollow, so as to allow the atmosphere from an underground flue to reach this opening freely.

When the mason-work is not employed the base-plate w is to be sustained upon legs, and the atmosphere preferably admitted through an opening in the floor, and passes through a sheet-metal cylinder to the opening in the said base-plate w. In either instance a portion of the atmosphere passes beneath the annular base b4, and ascends between the flanges a that support the furnace, and in close contact with the outside of the furnace, and an-r other portion passes up the inside central airlue c, and, coming in contact with the conical heated lire-pot and central Huecylinders, the atmosphere` not only becomes highly heated, but also tends to cool both the inside and outside portions of the furnace at the places most 4 exposed to the intense action of the lire.

An outer vsheet-metal Gasen), raised sufficiently from the floor, serves to inclose the warm air around the furnace, and make it circulate to the air pipes or tubes-that convey the heat to the portions of the building to be warmed.

I do not claim a stove or heater` in which there is a central air-flue passing through the re, as this has been employed. My invention relates to the mode of constructing the heater, whereby this central air-due land the other parts of the stove are combined, and 3. The base w, with a central opening for rendered more effective and less liable to inatmospheric air, and provided with ilanges or jury in use. p supports a for the furnace, in combination I claim as my inventionwith the annular fire space and. pots, substan- 1. The annular channel d and. ring-'frame c', tially as set forth.

in combination With the gratos e, Scrapers fi', Signed by me this 21st day of- October, 1875.

and means for revolving the grate, substantially as set forth. THOS. F. HEMMIOH. 2. The ring o, tubes r, and circular flue-pipe Witnesses: s,-in combination with the central air-casings GEO. T. PINOKNEY,

c n, and external casings l Z1 Z2, as set forth. HAROLD SERRELL. 

